Introduction: No epidemiological data exist concerning the influence of an earthquake on the risk of stroke. Whether the incidence of cerebrovascular stroke increased after the 1995 Hanshin-Awaji earthquake (EQ) in Japan and whether seismic intensity affected stroke risk dose-dependently was examined.
Methods: A retrospective cohort study was conducted among residents, who were living in two towns on the island of Awaji and were participants of the National Health Insurance (NHI) program. The two towns were divided into 11 districts and their respective damage and socioeconomic states were investigated. Reviewing the NHI documents issued before and after the EQ, people who had strokes (9th International Classification of Diseases, codes 430-431 or 433-434.9) were identified. Risk of stroke in relation to the seismic intensities, was assessed with the Cox proportional hazard model.
Results: Among subjects aged 40 to 99 years, 45 of 8,758 (0.514%) had a stroke the year before the EQ 72 of 8,893 (0.810%) had a stroke in the first year following the EQ, and 49 of 8,710 (0.566%) had a stroke in the second year following the EQ. In districts where the earthquake's intensity was < or = 9.5 on the modified Mercalli intensity (MMI), compared with the year prior to the EQ, the relative risk (RR) of stroke was 2.4 (95% confidence interval (CI) = 1.1, 5.0) in the first year following the EQ, after adjusting for age, gender, and income. In that year, compared with MMI of < 8.5-9.0, RRs for 9.0-9.5 and > or = 9.5 were 1.6 (CI = 0.9, 2.1) and 2.0 (CI = 1.1, 3.7), respectively (p for trend 0.02). No trend for the RR was observed in the year before the EQ or in the second year following the EQ.
Conclusion: The incidence of stroke increased in the first year following the EQ. The increase was associated with seismic intensity in a dose-response manner. Results suggest a potential threshold for RR of > or = 2.0 in areas near 9.5 on the MMI scale.
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http://dx.doi.org/10.1017/s1049023x00001928 | DOI Listing |
Sci Rep
January 2025
College of Civil and Transportation Engineering, Hohai University, No. 1 Xikang Road, Nanjing City, 210098, Jiangsu Province, People's Republic of China.
Aftershocks can cause additional damage or even lead to the collapse of structures already weakened by a mainshock. Scarcity of in-situ recorded aftershock accelerograms heightens the need to develop synthetic aftershock ground motions. These synthesized motions are crucial for assessing the cumulative seismic demand on structures subjected to mainshock-aftershock sequences.
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Engineering Institute, Veracruzana University, Juan Pablo II Avenue, Mocambo Campus, Costa Verde, Boca Del Rio City, Veracruz 94292, México.
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December 2024
PetroChina Dagang Oilfield Company, Tianjin 300280, China.
The Chenghai area is a secondary structural unit within the Qikou sag of the Bohai Bay Basin, located in the southern part of the Dagang offshore area, known for its abundant oil and gas resources. Influenced by multiple episodes of tectonic activity, the Chenghai area exhibits a highly developed fault system, which significantly impacts oil and gas exploration in the region. To investigate the structural characteristics of fault zones in the Chenghai area and their petroleum geological significance, this study builds upon previous research by utilizing oilfield drilling data and relevant seismic information.
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Orange Home Care Clinic, Fukui, Fukui, Japan.
PLoS One
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Xilinhot Earthquake Monitoring Center Station, Xilinhot, Inner Mongolia Autonomous Region, China.
Analysis of the continuous ambient noise data collected by a dense network of broadband seismic stations reveals the characteristics of ambient noise in densely populated urban areas. A study conducted in central Inner Mongolia utilized ten broadband stations to investigate two distinct repetitive and intense noise signals with predominant frequencies ranging from 1-20 Hz and 0.01-1 Hz.
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